package com.ctrip.framework.apollo.common.controller;

import com.ctrip.framework.apollo.common.exception.AbstractApolloHttpException;
import com.ctrip.framework.apollo.tracer.Tracer;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.web.HttpMediaTypeException;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.client.HttpStatusCodeException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Type;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.HashMap;
import java.util.Map;

import static org.springframework.http.HttpStatus.*;
import static org.springframework.http.MediaType.APPLICATION_JSON;

@ControllerAdvice
public class GlobalDefaultExceptionHandler {

    private Gson gson = new Gson();
    private static Type mapType = new TypeToken<Map<String, Object>>() {}.getType();

    private static final Logger logger = LoggerFactory.getLogger(GlobalDefaultExceptionHandler.class);

    // 处理系统内置的 Exception
    @ExceptionHandler(Throwable.class)
    public ResponseEntity<Map<String, Object>> exception(HttpServletRequest request, Throwable ex) {
        return handleError(request, INTERNAL_SERVER_ERROR, ex); // 500
    }

    @ExceptionHandler({HttpRequestMethodNotSupportedException.class, HttpMediaTypeException.class})
    public ResponseEntity<Map<String, Object>> badRequest(HttpServletRequest request, ServletException ex) {
        return handleError(request, BAD_REQUEST, ex); // 400
    }

    @ExceptionHandler(HttpStatusCodeException.class)
    public ResponseEntity<Map<String, Object>> restTemplateException(HttpServletRequest request, HttpStatusCodeException ex) {
        return handleError(request, ex.getStatusCode(), ex);
    }

    @ExceptionHandler(AccessDeniedException.class)
    public ResponseEntity<Map<String, Object>> accessDeny(HttpServletRequest request,
                                                          AccessDeniedException ex) {
        return handleError(request, FORBIDDEN, ex); // 403 接口要访问的资源未得到授权，比如只授权了对A应用下Namespace的管理权限，但是却尝试管理B应用下的配置。

    }

    // 处理自定义Exception
    @ExceptionHandler({AbstractApolloHttpException.class})
    public ResponseEntity<Map<String, Object>> badRequest(HttpServletRequest request, AbstractApolloHttpException ex) {
        return handleError(request, ex);
    }

    private ResponseEntity<Map<String, Object>> handleError(HttpServletRequest request, AbstractApolloHttpException ex) {
        return handleError(request, ex.getHttpStatus(), ex);
    }


    private ResponseEntity<Map<String, Object>> handleError(HttpServletRequest request, HttpStatus status, Throwable ex) {
        String message = ex.getMessage();

        // 打印错误日志
        logger.error(message, ex);
        Tracer.logError(ex);

        Map<String, Object> errorAttributes = new HashMap<>();
        boolean errorHandled = false;
        if (ex instanceof HttpStatusCodeException) {
            try {
                // try to extract the original error info if it is thrown from apollo programs, e.g. admin service
                errorAttributes = gson.fromJson(((HttpStatusCodeException) ex).getResponseBodyAsString(), mapType);
                status = ((HttpStatusCodeException) ex).getStatusCode();
                errorHandled = true;
            } catch (Throwable th) {
                //ignore
            }
        }

        if (!errorHandled) {
            errorAttributes.put("status", status.value());
            errorAttributes.put("message", message);
            errorAttributes.put("timestamp", LocalDateTime.now().format(DateTimeFormatter.ISO_LOCAL_DATE_TIME));
            errorAttributes.put("exception", ex.getClass().getName());
        }

        // 返回 ResponseEntity 对象，并返回
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(APPLICATION_JSON); // 设置为 application/json 返回
        return new ResponseEntity<>(errorAttributes, headers, status);
    }

}
